Our focus is Candida albicans, the predominant invasive fungal pathogen in the USA. Our goal is to develop a genetic tool and a resource of strains and data that facilitate understanding of essential C. albicans genes, hence prospective therapeutic targets. Our studies rely upon a systematic approach to create partially defective alleles, called DAmP alleles (decreased abundance by mRNA perturbation), that we have borrowed from S. cerevisiae geneticists. DAmP alleles are created by replacing the 3' noncoding sequence of a gene with sequences that lack efficient cleavage and poly-A addition sites, thus reducing nuclear export, stability, and translation of the mRNA. In pilot studies we have applied the approach successfully to the essential C. albicans genes CDC3, CDC12, IRE1, SNF1, DBF2, and orf19.5376. We seek to extend the approach by implementing two specific aims: (1) to create DAmP strains for 17 protein kinase-related genes and 50 cell wall-related genes, all of which we have been unable to disrupt with insertion mutations; and (2) to assign these genes to functional pathways through DAmP strain phenotypic analysis. Completion of these aims will provide new understanding of C. albicans gene function, focused on a set of genes prioritized to include prospective therapeutic targets. In terms of deliverables, the project will yield new methodological tools, a characterized strain collection, and a dataset that will benefit the C. albicans research community. In terms of overall impact, we foresee that our success with this approach will promote its implementation more broadly in C. albicans and in other eukaryotic pathogens. PUBLIC HEALTH RELEVANCE: Fungal pathogens cause lethal infections in over 10,000 Americans per year and add over $2.6 billion to our health care costs. New drugs are needed to address this health threat. Our project will develop a new method to understand drug targets in fungal pathogens.